package xiongguanweb.util

import javax.servlet.http.HttpServletRequest

class IPUtils {

    /**
     13      * 获取用户真实IP地址，不使用request.getRemoteAddr()的原因是有可能用户使用了代理软件方式避免真实IP地址,
     14 *
     16      * 可是，如果通过了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP值，究竟哪个才是真正的用户端的真实IP呢？
     17      * 答案是取X-Forwarded-For中第一个非unknown的有效IP字符串。
     18      *
     19      * 如：X-Forwarded-For：192.168.1.110, 192.168.1.120, 192.168.1.130,
     20      * 192.168.1.100
     21      *
     22      * 用户真实IP为： 192.168.1.110
     23      *
     24      * @param request
     25      * @return
     26      */
    static String getIpAddress(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for")
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP")
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP")
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_CLIENT_IP")
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR")
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr()
        }
        return ip
    }
}
